This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. We use the Computer Graphics Laboratory facilities to display and analyze molecular dynamics simulation results. Our research projects focus on a) refining, testing and developing the new generation of additive and nonadditive force field parameters;and b) macromolecular simulation using molecular dynamics. The work is being carried out to further develop the additive and nonadditive AMBER force field. The nonadditive AMBER parametrization includes nonadditive effects, based on atomic polarizabilities, and lone pairs interactions. A new approach to treat intra-molecular polarization has been proposed during charge development for nonadditive simulations. More thorough tests have been performed on DNA and small proteins using nonadditive force field with additional off-center (lone pairs) points located on electron-donating atoms. Additionally more tests have been performed on small protein such as ubiquitin, and short polyalanine peptides. Recently, molecular dynamics simulations have been performed in order to determine stability (free energies) and conformational transitions in short RNA loops: UUCG and UUUU.